in my WPF application, I have a DataGrid, which is bound to an ObservableCollection.
<DataGrid x:Name="DataGridTeilnehmer" HorizontalAlignment="Left" VerticalAlignment="Top" CellEditEnding="DataGridTeilnehmer_CellEditEnding" AutoGenerateColumns="False" SelectionMode="Single">
<DataGrid.Columns>
<DataGridTemplateColumn Header="Teilnehmer" CellEditingTemplate="{StaticResource TeilnehmerEditTemplate}" CellTemplate="{StaticResource TeilnehmerCellTemplate}" />
<DataGridComboBoxColumn Header="Pass" />
...
The DataGridComboBoxColumn shall be filled with individual values for each row. The values depend on the entry of the first column. So, I would like to set the data in the CellEditEnding event like this:
private void DataGridTeilnehmer_CellEditEnding(object sender, DataGridCellEditEndingEventArgs e)
{
if (!commiting)
{
commiting = true;
DataGridTeilnehmer.CommitEdit(DataGridEditingUnit.Row, false);
commiting = false;
// check, whether it is the first column that has been edited
if (...)
// get the list<string> for the combobox depending on the edited content
// get the combobox of the current row and bind the calculated list<string> to it
}
}
}
How can I do this?
EDIT: An example of what I am trying to achieve.
I have list of customers, which have individual tickets each. When the customer has been chosen in the first column, I want to load the ticket-list this customer has and load it into the next column - the combobox column.
Thanks in advance,
Frank
If you bound your datagrid to an ObservableCollection and your object implements INotifyPropertyChanged you can achieve what you need without using cell editending event.
In your model just check the value of your first column then set others columns values:
private string _firstColumn;
public string FirstColumn
{
get { return _firstColumn; }
set {
_firstColumn = value;
if(value == ...)
//set other properties
...
//notify the change
OnPropertyChanged("FirstColumn"); }
}
when your datagridrow lost focus all the new values will be notified to the datagrid
Related
I have a requirement where I need to bind a list of observable collections to the item source of dynamically created ComboBoxes.
The problem is we bind through xaml conventionally in ItemsSource property but now the control rows in the grid are being added dynamically so each ComboBox in a row reference to the same collection whereas I need to bind it to a separate collection in observable collection list each time a row in the grid is added.
This what I have tried so far, any guidance would be appreciated. Thanks.
public virtual List<ObservableCollection<ComboBoxEntity>> ListRewardRule { get; set; }
Xaml :
<itimControls:ComboBox Name="cboReward"
IsMandatory="True"
itimComponents:ComponentManager.ComponentId="TXT_GROUP_RULE"
MaxWidth="400"
MinWidth="150"
ItemsSource="{Binding ListRewardRule, ElementName=RDefinitionScreen}"
DisplayMemberPath="Name"
SelectedValuePath="Code"
Loaded="cboReward_Loaded"
SelectedValue="{Binding RewardRuleId, Mode=TwoWay}"
SelectionChanged="cboReward_SelectionChanged">
</itimControls:ComboBox>
.CS :
private void cboReward_Loaded(object sender, RoutedEventArgs e)
{
Itim.Framework.Silverlight.UI.Controls.ComboBox cboReward = ((Itim.Framework.Silverlight.UI.Controls.ComboBox)sender);
int row = (int)cboReward.GetValue(Grid.RowProperty);
if (Model.ListRewardRule.Count > 0)
{
var rewardGroups = Model.RewardGroupAndTier.RewardGroups;
if(rewardGroups.Count > 1)
{
cboReward.ItemsSource = Model.ListRewardRule[row];
}
}
}
The way I understand this is, you have a “grid” (I suppose you mean a DataGrid) and each row in the grid has, among other things, a set of combo boxes.
What I’d do is bind that grid to an ObservableCollection of a custom class, call it CustomRowClass. CustomRowClass should have an ObservableCollection that will be bound to the combo boxes.
The magic is to define a DataTemplate for CustomRowClass. Once you set up the XAML this way, all you need to do is create an instance of CustomRowClass, and then add it to the ItemsSource of the grid.
In my WPF application, I am developing a fairly straightforward page that allows either creating a new object or choosing one from a combo box, then editing the object.
One of the parts of the object that is editable is a related database table in a one-to-many relationship, so for that piece I used a DataGrid. The DataGrid itself has a data-bound ComboBox column, as you can see here:
<DataGrid AutoGenerateColumns="False" EnableRowVirtualization="True"
CanUserAddRows="False" CanUserDeleteRows="True"
ItemsSource="{Binding Path=No.Lower_Assy}"
DataGridCell.Selected="dgAssy_GotFocus">
<DataGrid.Columns>
<DataGridTemplateColumn Header="Number & Type">
<DataGridTemplateColumn.CellTemplate>
<DataTemplate>
<ComboBox ItemsSource="{Binding Path=DataContext.ComboSource, RelativeSource={RelativeSource AncestorType=Page}}"
SelectedValuePath="bwk_No"
SelectedValue="{Binding Path=fwf_Higher_N, ValidatesOnDataErrors=True, ValidatesOnExceptions=True, NotifyOnValidationError=True, UpdateSourceTrigger=PropertyChanged}">
<ComboBox.ItemTemplate>
<DataTemplate>
<StackPanel Orientation="Horizontal">
<TextBlock Text="{Binding Path=Number}"/>
<TextBlock Text="{Binding Path=Type}"/>
</StackPanel>
</DataTemplate>
</ComboBox.ItemTemplate>
</ComboBox>
</DataTemplate>
</DataGridTemplateColumn.CellTemplate>
</DataGridTemplateColumn>
<!-- other text columns omitted -->
<DataGridTemplateColumn>
<DataGridTemplateColumn.CellTemplate>
<DataTemplate>
<Button Content="Delete" Click="btnDeleteHigherAssy_Click" />
</DataTemplate>
</DataGridTemplateColumn.CellTemplate>
</DataGridTemplateColumn>
</DataGrid.Columns>
</DataGrid>
Code behind:
private void dgAssy_GotFocus(object sender, RoutedEventArgs e)
{
if (e.OriginalSource.GetType() == typeof(DataGridCell))
{
// Starts the edit on the row
DataGrid grd = (DataGrid)sender;
grd.BeginEdit(e);
}
}
And for the save button:
private void btnSave_Click(object sender, RoutedEventArgs e)
{
if (CanUserEdit())
{
if (string.IsNullOrWhiteSpace(model.Data.Error))
{
repo.Save(model.Data);
StatusText = STATUS_SAVED;
model.CanSave = false;
// This is the data source for the main combo box on the page
model.ComboSource = repo.GetData();
// Set the combo box's selected item, in case this is a new object.
// cboNo is the main combo box on the page which allows selecting
// an object to edit
// Apparently setting SelectedItem directly doesn't work on a databound combo box
int index = model.ComboSource.ToList().FindIndex(x => x.bwk_No == model.Data.bwk_No);
cboNo.SelectedIndex = index;
}
else
{
MessageBox.Show("Invalid data:\n" + model.Data.Error, "Cannot save");
}
}
}
The problem
When I choose an item from the combo box in the data grid, it seems to work until I click on the save button. Then two things happen:
The combo box's selected item is set to null, blanking out the combo box.
As a result of (1), the save button is re-enabled because the data has changed. (The save button is bound to model.CanSave, which as you can see is set to false in the button handler; it is set to true by a property change event handler if there are no data errors.)
Why is it being reset? I've followed the code flow closely and can see the property change event for the combo box's backing field (fwf_Higher_N) being handled, and it appears to somehow come from the line model.ComboSource = repo.GetData();, but the stack only shows [external code] and I don't see why that line would modify an existing object.
The model class
// Names have been changed to protect the innocent
private class MyDataViewModel : INotifyPropertyChanged
{
private DbData _Data;
public DbData Data
{
get { return _Data; }
set
{
_Data = value;
OnPropertyChanged("Data");
}
}
private IQueryable<MyComboModel> _ComboSource;
public IQueryable<MyComboModel> ComboSource {
get { return _ComboSource; }
set
{
_ComboSource = value;
OnPropertyChanged("ComboSource");
}
}
private bool _CanSave;
public bool CanSave
{
get { return _CanSave; }
set
{
_CanSave = value;
OnPropertyChanged("CanSave");
}
}
public event PropertyChangedEventHandler PropertyChanged;
protected void OnPropertyChanged(string name)
{
PropertyChangedEventHandler handler = PropertyChanged;
if (handler != null)
{
handler(this, new PropertyChangedEventArgs(name));
}
}
}
Your description of what is going on and your markup doesn't quite match. I'm going to make some assumptions, such as that Page.DataContext is an instance of MyDataViewModel.
I'm sorry to say it, but a SSCCE would do wonders here. I strongly suggest when anyone gets into situations where they are elbow deep in code they don't quite understand that they break out what they are attempting to do and create a minimal prototype that either exhibits the same behavior, or that helps you learn what's going wrong. I've made 500+ prototypes in the past five years.
As for this situation, you refer to a ComboBox named cboNo in btnSave_Click, but I don't see that in the xaml. This ComboBox's ItemSource appears to be bound to MyDataViewModel.ComboSource.
In addition, all ComboBoxes in the DataGrid also appear to be bound to the model's ComboSource. And, in the button handler event, you change what is in the property:
// This is the data source for the main combo box on the page
model.ComboSource = repo.GetData();
This fires PropertyChanged, and every ComboBox bound to this property will be updated. That means not only cboNo but also every ComboBox in the DataGrid.
It is expected behavior that, when ComboBox.ItemsSource changes, if ComboBox.SelectedItem is not contained within the items source, that SelectedItem is nulled out.
I just spun up a prototype (501+) and it appears that if the IEnumerable that the ComboBox is bound to changes, but the elements in the IEnumerable do not, then SelectedItem is not nulled out.
var temp = combo.ItemsSource.OfType<object>().ToArray();
combo.ItemsSource = temp;
So, within the btnSave_Click event handler, you change this ItemsSource, which probably does not have the same instances that are already in the combo, thus nulling out SelectedItem for all ComboBoxes bound to this property, and then only update cboNo's SelectedIndex.
Now, as for what to do about it...
Well, not sure. From the rest of your code, it appears you need to do some more codebehind work to make sure only the necessary ComboBoxes have their sources updated...
I'm a bit new to WPF and .NET, so this may be a simple task:
I have textblocks that get their values from the selected item of a datagrid. I'm trying to bind a combobox to one column in that datagrid so the user sees all the values in that datagrid column. When selecting an item in the combobox, it should make that row the selected item in the datagrid as well.
Here is my DataGrid:
<sdk:DataGrid AutoGenerateColumns="True" Name="l1dGrid" IsReadOnly="True" ItemsSource="{Binding}" DataContext="{Binding Path=DataContext}" />
and here is where the Datagrid gets data loaded:
_PCContext.Load(_PCContext.GetLine1_DownstairsQuery());
l1dGrid.ItemsSource = _PCContext.Line1_Downstairs;
Now I just need a combobox to have the ability to change the selected item in the DataGrid.Thanks in advance for any assistance!!!
[EDIT - SOLVED]
Ok, so I ended up just querying the datagrid based on the selected item of the combobox and setting the datagrid selected item to the one that matched that query.Here is the code I used to do this:
private void stockPick_comboBox_SelectionChanged(object sender, SelectionChangedEventArgs e)
{
string selection = stockPick_comboBox.SelectedValue.ToString().Replace("Line1_Downstairs : ", "");
selectGridItem(selection);
}
private void selectGridItem(string selection)
{
var stock = (from i in _PCContext.Line1_Downstairs
where i.Stock == selection
select i).FirstOrDefault();
l1dGrid.SelectedItem = stock;
}
I would like to bring a row of my data grid into view programatically. I have a more than 100 rows. When I create a row(which I am doing by adding an item to a observable collection) I would like that new row to be selected and bring that into view. I was able to select the new row in my code but could not do the scrolling. More over I want the first cell of the row to be in edit mode so that the user can input text. I am following MVVM pattern for the application and would like to keep zero code in my views. How Can I achieve this?
Any help or suggestion will be appreciated....
Update:
This what I did in my XAML
<telerik:RadGridView ItemsSource="{Binding AllPartClasses}"
SelectedItem="{Binding SelectedPartClassViewModel, Mode=TwoWay}"
SelectionMode="Single" IsSynchronizedWithCurrentItem="True">
in my view model I did this
void AddNewPartClassExecute()
{
PartClass newPartClass = new PartClass();
PartClassViewModel tempPartClass = new PartClassViewModel(newPartClass);
tempPartClass.IsInValid = true;
AllPartClasses.Add(tempPartClass);
SelectedPartClassViewModel = tempPartClass;
Global.DbContext.PartClasses.AddObject(newPartClass);
//OnPropertyChanged("AllPartClasses");
}
public PartClassViewModel SelectedPartClassViewModel
{
get
{
return _selectedPartClassViewModel;
}
set
{
_selectedPartClassViewModel = value;
OnPropertyChanged("SelectedPartClassViewModel");
}
}
It did not work for me.
For the regular WPF DataGrid you can use ScrollIntoView. In your view hookup the SelectionChanged event to the following in your view code-behind cs file.
private void OnSelectionChanged( object sender, SelectionChangedEventArgs e )
{
Selector selector = sender as Selector;
DataGrid dataGrid = selector as DataGrid;
if ( dataGrid != null && selector.SelectedItem != null && dataGrid.SelectedIndex >= 0 )
{
dataGrid.ScrollIntoView( selector.SelectedItem );
}
}
When following MVVM pattern you should not do a UI-specific stuff like scrolling from a code.
Solution would be simple - just bind DataGrid.SelectedItem to a property in ViewModel and when adding a new item in the items collection just update a property bound to SelectedItem so it would reference to just added item and data grid should select an appropriate row automatically.
<DataGrid
ItemsSource="{Binding UnderyingItemsCollection}"
SelectedItem="{Binding RecentlyAddedItem, Mode=TwoWay}"
IsSynchronizedWithCurrentItem="True">
I have a DataGridCell that contains a ComboBox.
I want, that when I fire 'SelectionChanged' event of it, a CollectionViewSource of a different column (eventually - at runtime, cell) CellEditingTemplate's Resources should be populated with data according to the selected value for this row.
Maybe DataTrigger, ActionTrigger, EventTrigger, maybe by code, XAML I don't care, I just need a solution.
Thanks a lot!
Related: Accessing control between
DataGridCells, dynamic cascading
ComboBoxes
If I understand your question right, you will fill the contents of a combobox in a cell based on the selection of a combobox in another cell that is in the same row of the DataGrid.
If yes:
First Solution (IMO the preferable)
Make a ViewModel that represents the rows data (a simple wrapper around your data object). Bind the ItemsSource-property of the destination ComboBox to a IEnumerable-property that you provide from your viewmodel.
Bind the SelectedItem from the source-ComboBox to another property of your ViewModel. Every time this source-property changes in your ViewModel, you change the contents of the list that is provided by the ViewModel.
Use for the desintation (list) property a ObservableCollection<T>. The source property is up to you.
Here is an approximately example. I call the class VM (for ViewModel) but this changes nothing on your current solution. MVVM can also be used partial.
public class DataObjectVM : DependencyObject {
public static readonly DependencyProperty SelectedCategoryProperty =
DependencyProperty.Register("SelectedCategory", typeof(CategoryClass), typeof(DataObjectVM), new FrameworkPropertyMetadata(null, FrameworkPropertyMetadataOptions.BindsTwoWayByDefault,delegate (DependencyObject d,DependencyPropertyChangedEventArgs e){
((DataObjectVM)d).SelectedCategoryChanged(e);
}));
ObservableCollection<ItemClass> _items=new ObservableCollection<ItemClass>();
void SelectedCategoryChanged(DependencyPropertyChangedEventArgs e) {
// Change here the contents of the _items collection.
// The destination ComboBox will update as you desire
// Do not change the _items reference. Only clear, add, remove or
// rearange the collection-items
}
// Bind the destination ComboxBox.ItemsSource to this property
public IEnumerable<ItemClass> DestinationItems {
get {
return _items;
}
}
// Bind to this property with the source ComboBox.SelectedItem
public CategoryClass SelectedCategory {
get { return (CategoryClass)GetValue(SelectedCategoryProperty); }
set { SetValue(SelectedCategoryProperty, value); }
}
}
Add a constructor to this class that takes your data object and make some wrapper properties to the rest the properties you need to provide in the DataGrid. If they are alot, you can also make one property that provides your data object and the bind directly to it. Not nice, but it will do the job.
You also can (must) pre-initialize the SelectedCategory with data from your business object. Do this also in the constructor.
As a ItemsSource for the DataGrid you give an IEnumerable of the DataObjectVM-class that wrapps all items you want to show.
Alternative way with VisualTreeHelper
If you want to do it manual, register in the code behind a handler for the ComboBox.SelectionChangedEvent and change then the ItemsSource of the destination ComboBox manual. The business-object you will get with the EventArgs. The destination ComboBox you must search in the visual tree (Use the VisualTreeHelper). The events can be wired also if you use the DataGridTemplateColumn class and add a DataTemplate with the corresponding ComboBoxes.
But I think this is realy not very simple to do and can be error prone. The above solution is much easier.
Here is the code you propably are looking for:
private void CboSource_SelectionChanged(object sender, SelectionChangedEventArgs e) {
ComboBox cbo = (ComboBox)sender;
FrameworkElement currentFe = VisualTreeHelper.GetParent(cbo) as FrameworkElement;
while (null != currentFe && !(currentFe is DataGridRow)) {
currentFe = VisualTreeHelper.GetParent(currentFe) as FrameworkElement;
}
if (null != currentFe) {
List<ComboBox> list = new List<ComboBox>();
FindChildFrameworkElementsOfType<ComboBox>(currentFe,list);
// Requirement 1: Find ComboBox
foreach (ComboBox cboFound in list) {
if (cboFound.Name == "PART_CboDestination") {
// This is the desired ComboBox
// Your BO is available through cbo.Found.DataContext property
// If don't like to check the name, you can also depend on the
// sequence of the cbo's because I search them in a deep search
// operation. The sequence will be fix.
}
}
List<DataGridCell> cells = new List<DataGridCell>();
FindChildFrameworkElementsOfType<DataGridCell>(currentFe,cells);
// Requirement 2: Find Sibling Cell
foreach (DataGridCell cell in cells) {
// Here you have the desired cell of the other post
// Take the sibling you are interested in
// The sequence is as you expect it
DataGridTemplateColumn col=cell.Column as DataGridTemplateColumn;
DataTemplate template = col.CellTemplate;
// Through template.Resources you can access the CollectionViewSources
// if they are placed in the CellTemplate.
// Change this code if you will have an edit cell template or another
// another construction
}
}
}
void FindChildFrameworkElementsOfType<T>(DependencyObject parent,IList<T> list) where T: FrameworkElement{
DependencyObject child;
for(int i=0;i< VisualTreeHelper.GetChildrenCount(parent);i++){
child = VisualTreeHelper.GetChild(parent, i);
if (child is T) {
list.Add((T)child);
}
FindChildFrameworkElementsOfType<T>(child,list);
}
}
And this is the markup I used:
<DataGrid.Columns>
<DataGridTemplateColumn Header="Source" >
<DataGridTemplateColumn.CellTemplate>
<DataTemplate>
<ComboBox Name="PART_CboSource" SelectionChanged="CboSource_SelectionChanged" ItemsSource="!!YOUR ITEMS SOURCE!!" SelectedItem="{Binding Category}">
</ComboBox>
</DataTemplate>
</DataGridTemplateColumn.CellTemplate>
</DataGridTemplateColumn>
<DataGridTemplateColumn Header="Destination">
<DataGridTemplateColumn.CellTemplate>
<DataTemplate>
<ComboBox Name="PART_CboDestination"/>
</DataTemplate>
</DataGridTemplateColumn.CellTemplate>
</DataGridTemplateColumn>
</DataGrid.Columns>
Accessing the CollectionViewSource
To access the CollectionViewSource, put it into the resources section of the corresponding DataTemplate, not of the panel, then you will have direct access to them. IMO is this location anyway more appropriate than the resources-container of the grid.
If you dont't want to do this, check the state of the following post:
How to get logical tree of a DataTemplate